How Low Power Mode in iOS 9 Will Save Your Battery

When Apple announced iOS 9 a few weeks back they gave us a tantalizing glimpse at a number of interesting new features. For instance, we got an intriguing look at the new Proactive Assistance functionality, and a solid demo of the upgraded Notes app too. But perhaps the best new feature is one that Apple mostly mentioned just in passing, although it provides a service that most iPhone users will almost certainly welcome. That new feature is called Low Power Mode, and it seems like just the thing for those who find themselves running low on battery life at the most inopportune times.

While not a lot is known about Low Power Mode just yet, we do know that Apple included it in iOS 9 to help extend battery life further. It isn’t clear just how much of an extension to our battery life we should expect while in LPM, but early reports from beta versions of the new mobile operating system seem to indicate that it is quite effective.

To use Low Power Mode, users must first activate it the Settings app. Then, when their phone’s battery supply drops below 20%, they’ll receive the usual warning that they are running low on juice. That warning, which also appears when the iPhone’s battery hits 10% of its life, will now give users the option to activate Low Power Mode. If they choose to do so, the battery life indicator will turn yellow as a reminder that the phone is now sipping power.

These kinds of energy saving modes are not new to the smartphone world of course, as Android users have had similar options for several years now. But most Android implementations of Low Power Mode greatly reduce the functionality of the phone when activated, often turning the device into a dumb phone that can only make voice calls and send texts. Other implementations of LPM will even take such extreme measures as shifting the phone’s display into a grayscale mode to help conserve as much energy as possible.

But Apple’s Low Power Mode doesn’t work like that. In fact, there is very little functionality on the phone that stops working at all. Instead, the iOS 9 development team elected to down-clock the speed of the iPhone’s CPU and kill most background services instead. In other words, performance drops significantly, but your phone continues to operate in a state that is very close to normal.

So just how much of a performance hit does Lower Power Mode inflict on our iPhones? According to recent benchmark tests conducted by Mac Rumors, it appears that turning on LPM will cause the performance of most iPhones to drop as much by as much as 40%. That means that a relatively fast iPhone 6 would be reduced to about the same performance level as an iPhone 5 or 5S when in Low Power Mode.

Those performance gains could prove to be very beneficial, especially when you’re away from a charger and your battery is nearly depleted. Mac Rumors says that in their testing, activating Low Power Mode allowed their iPhones to stay active for up to three additional hours. That may not sound like much, but when you’re in an emergency situation, those three hours will come in very handy.

We’ll have to wait until iOS 9 is released sometime this fall (I’m betting on late September) before we’ll truly know just how useful Low Power Mode can be. But at this early stage, it is looking very promising indeed.

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About Kraig Becker

Kraig Becker is a freelance writer based out of Nashville, TN. His two passions are technology and travel, which are also the two things he most likes to write about. An avid Apple fan, he bought his first Mac back in 1990, and has and has been using the company's computers, and other devices, ever since.